BDO interprets the widening gulf between CEO and CFO compensation as a reflection of the higher number of CEOs getting performance-based pay --- a category that has done particularly well of late. As more CFOs are paid that way, the pay gulf could narrow.

Not surprisingly, the research also shows broad differences in pay on an industry basis, with real estate recording the highest pay levels in the mid-market: $1.30 million and $3.36 million for CFOs and CEOs, respectively. Less expected, perhaps, is that that banking turns out to be the lowest-compensated category, with finance chiefs averaging $442,425, and chief executives averaging $1.04 million.

Technology CFOs and CEOs were only slightly behind their real-estate sisters and brothers. Tech finance chiefs averaged 1.16 million, 37.9% of the $3.01 million average for tech CEOs.

The narrowest gap between CFO and CEO pay was registered in health care, where the $944,861 average for finance chiefs was 46.6% of the $2.03 million earned by their bosses. The widest chasm? In the non-banking area of financial services, CFOs made only 34.2% of what the CEOs were paid: $741,711 versus $2.17 million.